Cable seal



Dec'.v 19, 1961 R. C. WILSON CABLE SEAL Filed April 7, 1958 Fig- 2INVENTOR. RONALD C. WILSON Agent 3,013,824', CABLE SEAL Ronald C.Wilson, Granada Hills, Calif., assignor to Lockheed AircraftCorporation, Burbank,d Calif. Filed Apr. 7, 1958, Ser. No. 726,7@

Claims. (Cl. 256-16) This invention relates to sealing devices, andrelates more particularly to devices for sealing abouty control cablesand other movable control elements where they pass through pressurebulkheads, and the like.

ln aircraft designed for high altitude flying it is now the commonpractice to pressurize the fuselage so that an internal air pressurecondition may be maintained which is conducive to the comfort and wellbeing of the passengers and crew. Thecontrol systems of aircraft usuallyembody cables which extend from the interior of the fuselage or lllightcompartment to the control elements. These cables pass through openingsin the pressure bulkhead, and means must be provided to prevent theescape of the cabin air pressure from around the cables.y It isimportant that an eifective seal be maintained at each cable under thewidely varying temperature conditions encountered during high altitudetlight. Furthermore, it is importantthat the f rictional resistance tocable movement offered by the sealing devices be kept at a minimum underall conditions of operation and flight so that the pilot has a fullsense of' feelfin operating the controls.

The current practice of sealing cables is done by threading the cablethrough a relatively thick, solid material, with the clearance hole assmall as possible. The present invention provides a seal which employsthe reverse process; that is, the cable is allowed to pass through alarge opening in which is placed a soft, llexible medliun capable ot'sealing the cable completely. Generally, the cable is placed in a mediumof densely stacked bristles in Contact with the cable. The bristles aresuitably retained in a cylindrical housing and the housing is packedwith a suitable sealing compound.

lt is a general object of this invention to provide a cable seal usefulat a pressure bulkhead, or the like, that reduces air leakage to aminimum and that has low fric tional resistance to cable movement. Thecable seal of this invention keeps the air pressure leakage at anacceptable minimum when initially installed, as well as after extendedservice and while under a considerable pressure differential.

Another object of this invention is to provide a cable seal that issimple and compact, requiring a minimum of space at the bulkhead. Thesmall compact sealing device of the invention does not interfere withthe installation of pulleys in adjacent relation to the bulkhead or withthe operation of cables over pulleys so positioned.

lt is a further object of the present invention to provide a cable sealarrangement which has a seal opening or run-through for a cable which isas large as possible and yet which will prevent pressure leakage.

Other objects and features of the invention will be readily understoodfrom the following detailed description of a typical preferred form ofthe invention wherein reference will be made to the accompanyingdrawings in which FIGURE l is a longitudinal cross sectional view of acable seal of the invention in the operative position on a bulkhead; and

FIGURE 2 is a cross sectional view of the cable seal of FIGURE l takenin the direction of arrows 2 2.

The sealing device of the present invention is capable of considerablevariation for adaption for specific installations. Furthermore, thedevice may be constructed to seal about single cables or control elementor a plurality of such members. ln the following detailed description,

3,013,824 Patented Dec. 19, 1.961

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a typical preferred form ofthe invention asl employed to seal aboutconventional control cables `willbe described, it being understood thatthe invention is ynot to be construed as limited or restricted to theparticular details herein set forth.` l

In the drawings, the sealing device is adapted vto be installed on abulkheadV Ato seal about a single cableV C and the device may be said toVcomprise generallya cylindrical body 10 having end retainers l1 and 12which are suitably crimped or formed about the opposite ends of the body10 to hold a sealing means 9 within thebody for sealing about the cableC. The cable may be employed without a covering or as shown in thedrawings a covering 13 is provided which presents a smooth cylindricalplastic surface. ln the present instance, a tetralluorethylene materialhas been found satisfactory. v

VThe body 1li is a one-piece tubular metal member having a longitudinalcavity 14 whichis considerably larger,v

in diameter than the kcable C so that the cable may pass through thebody without interference. The body is vof suliicient length to entendthrough an opening 1,5 in the bulkhead A and thenv project some distancefromthe inner or pressure side P of the bulkhead. lThe body l0 isretained within opening l5 and is secured tobulkhead Abby means of anannular flange 16 which is fastened to the bulkhead by means of rivets17. Flange 16v is provided with a coflar l which surroundsthe body llland is secure-d thereto by suitable means such as welds 20.

The sealing or packing means 9 is contained within body lll andcomprises, from the left `hand side of FIG- URE l, a lirst pair ofTeflon washers 30 and 31 separated by an arrangementof Orlon washers32-35 inclusive, a sealant 36, a multiplicityy of Nylon bristles 37impregnated with sealant, and a second pair of Teflon washers 40 and 41separated by another arrangement of Orlon washers 42-45 inclusive and arubber washer 46. The Tellen washers 30, 31 and dll, 4l are employed asanti-friction washers in the event the cable is momentarily displaced.yThe inside diameter of each Teflon washer is intentionally made largerthanpthe outside diameter of the cab'e including covering 13 ,so that aslight clearanceY is provided which prevents rubbing of the cableagainst the Teflon washers during normal operation of theV cable. TheTeflon washers are arranged in pairs to hold the multiplicity of Orlonwashers in position. The Orlon washers are provided with an insidediameter which is engageable with the covering 13 of the cable C and areused in combination with the Tellon covering to reduce friction wear asthe cable is displaced through the seal. The Orlon washers areparticularly useful in this application since the Orlon compositionoffers qualities of non-fraying which is normally encountered whenwashers of liber composition are employed.

The sealant 36 is employed to substantially prevent air from passingthrough body 10 and in the present instance, it has been founddesirableto employ a grease composition as the sealant. It is to be understoodthat although grease affords certain lubricating qualities, the sealingdevice of the present invention does not require anyV type of lubricantand the grease employed is solely for purposes of a sealant.

Located adjacent the sealant 36 and Teflon washer 40, there is provideda plurality of Nylon bristles represented by the general referencenumber 37 which are impregnated with the grease sealant 36. The extremefree ends of the bristles are in direct contact with the covering 13 andthe bristles are preferably composed of Nylon which cooperates with theTeflon covering 13 to reduce* frictional wear between the parts whilethe cable is moving. For the convenience of installation and formaintaining Teflon washers 31 and 40 in position, an annular steelsleeve 47 is provided into which the impregnated Nylon bristles may beinserted so that the sleeve may be conveniently slipped into cavity 14during initial installation. The sealant 36 and the sleeve 47 cooperateto maintain Teon washers 31 and 40 in their respective positions.

The rubber washer 46 is employed to seal the inside diameter of body andacts as a retainer in conjunction with Telion washers 4t) and 4l toretain Orlon washers 42-45 inclusive. inasmuch as Washer 46 is ofresilient composition, substantially the left-hand side of the sealingor packing means 9 acts in a manner somewhat similar to a piston.Thereby, the sealing or packing means 9 represents a combined static anddynamic sealing means for preventing the exchange of air betweencompartments separated by bulkhead A even though the pressuredifferential between the compartments is substantial.

From the above detailed description, it is believed that it will beapparent how the cable seal may be employed at the bulkhead A tomaintain airtight sealing around cables. The air pressure at the innerside P of the bulkhead A holds the packing 9 in sealing engagement withthe periphery of the cable cover 13 to prevent leakage around theexterior of the cable. The sealing means of the present invention offersa minimum of resistance to the movement of the cable and is notsusceptible to leakage under varying pressure and temperatureconditions.

Having described only a typical form of the invention, I do not wish tobe limited to specilic details herein set forth, but wish to reserve tomyself any variations or modifications that may appear to those skilledin the art or fall within the scope of the following claims:

I claim:

1. A device for sealing comprising a body of rigid material having alongitudinal cavity, a multiplicity of sealing bristles secured in thecavity, a supply of sealant stored adjacent the bristles within thecavity and impregnating the bristles to prevent the passage of airthrough the cavity, and retainers xed on the opposite ends of the bodyfor retaining the stored sealant and bristles within the cavity underslight pressure to insure constant impregnation of the bristles withsealant.

2. A device for sealing about a member comprising a body of rigidmaterial having a longitudinal cavity for receiving the member, amultiplicity of sealing bristles secured in the cavity about the member,a supply of flowable sealant stored adjacent the bristles within thecavity and impregnating the bristles to prevent the passage of airthrough the cavity, a plurality of soft, pliable washers arranged withinthe cavity to enclose the sealant and the bristles in cooperation withthe body, and retaining caps tixed on the opposite ends of the body andextending into the cavity t0 engage the plurality of washers forretaining the sealant and bristles within the cavity and under slightpressure to insure constant impregnation of the bristles with sealant inContact with the periphery of the member.

3. The invention as defined in claim 2 wherein, selected washers haveinside diameters substantially larger than the outside diameter of themember to provide a clearance therebetween, and wherein other selectedwashers have inside diameters in communication with the periphery of themember.

4. A device for sealing comprising a body of rigid material having alongitudinal cavity, a multiplicity of sealing bristles disposed in thecavity, a sealant disposed adjacent the bristles within the cavity andimpregnating the bristles for sealing the cavity, a first group ofwashers disposed within the cavity adjacent the sealant, a second groupof washers disposed within the cavity adjacent the bristles, the lirstand second groups of washers arranged to enclose the sealant andbristles within the cavity, and retaining caps xcd on the opposite endsof the body engageable with the first and second group of washers forretaining the sealant and bristles within the cavity.

5. The invention as defined in claim 4 wherein the second group ofwashers includes at least one washer of resilient composition, which isyieldable under pressure to permit longitudinal movement of the iirstgroup of Washers, the sealant and the bristles within the cavity.

References Cited in the tile of this patent UNITED STATES PATENTS1,109,826 Doble Sept. 8, 1914 2,390,928 Del Mar et al. Dec. 1l, 19452,517,693 Mead et al Aug. 8, 1950 2,845,286 Case et al July 29, 1958FOREIGN PATENTS 702,862 Germany Ian. 23, 1941

